I've done it, no big deal. Bought a flatbar on craigslist. Bought a pair of trigger shifters and brake levers online. Swapped them out. Works like a charm. In fact, the brakes are much better now. I did this to a 2008 Specialized Sequioia Elite with a triple front and 9-speed back. Also added grips (of course). I like the bike much better now.